Bleach-fix compositions and process for producing colored photographic images



United States Patent M 4 Claims. (or. 96-60) This invention relates to an improved processing for exposed color photographic materials, in which bleachfixing baths and also stop-fixing baths are used, which baths contain reducing agents.

In the conventional processing of exposed color photographic materials, the material, after development generally is rinsed or treated in a stop fixing bath. Thereafter, the metallic silver formed in the development is oxidised in .a bleach-fixing Ibath. Generally, complexes of trivalent iron or cobalt are used as oxidising agents in this case. The silver compound formed is fixed together with the residual silver halide.

The rinsing and treatment with the stop-fixing =bath between the developing bath and the bleach-fixing bath serves primarily for the removal of the excess developer substance and the alkali from the photographic layer. However, this is generally not achieved completely, so that certain proportions of developer substance pass into the oxidising bleach-fixing bath. In this bath, the developer is oxidised to form products which react with the color couplers incorporated into the photographic layers, so that more especially color fogging occurs in the uppermost layer.

This fogging can be prevented if the pH value of the processing baths following the developer bath are adjusted to a value of 7, so that no coupling can occur. This applies more especially in respect of the bleach-fixing bath, of which the pH values can be between 6.3 and 7. In these bleach-fixing baths, however, a serious disadvantage arises, namely that the cyan dyestuffs, which are formed by coupling of a naphthol derivative with the oxidation product of a p-iphenylene diamine derivative, are partially destroyed, the amount destroyed depending on the Redox potential value of the respective bath and the destruction being stronger as the pH value of the bath is lower.

Accordingly, only a very narrow pH range exists for a bleach-fixing bath, in which on the one hand no color fogging occurs and, on the other hand, the density of the cyan dyestuff is not reduced. In addition, a bleachfixing bat-h having a pH value below 7.0 has the disadvantage that it destroys more cyan dyestuff when fresh than when used.

The aforementioned disadvantages could therefore be avoided either by working at pH values below 7 and preventing the retrogression of the cyan image with suitable additives or other measures, or by working at pH values above 7 and suppressing the formation of a color fogging by introducing additives.

The invention has for its object the solution of the last-mentioned problem.

It has now been found that it is possible to work without disadvantageous consequences with bleach-fixing baths 3,293,036 Patented Dec. 20, 1966 and/or stop-fixing baths, etc., which have a pH value above 7, if certain reducing agents are added to these alkali baths. After numerous known reducing agents have proved to be inoperative, it was surprisingly found that hydrazine salts, hydroxyl ammonium salts and formarnidine-sulphinic acid completely prevent the formation of color fogging. The substances used according to the invention are used in quantities of advantageously 0.2 to 5 g. per litre of aqueous processing bath. The compounds can either be added to the bleach-fixing bath or to other baths which are used in the processing step between the developer and the bleach-fixing bath, for example, stop-baths or stop-fixing baths.

In addition to simple hydrazine or hydroxyl ammonium salts, the water-soluble derivatives of these two compounds can also be used for the present purpose.

With this method of processing, the cyan dyestuif is maintained fully and, in addition, the thiosulphate of the alkaline bleach-fixing bath is washed out during the subsequent rinsing in a shorter time than when using acid bleach-fixing baths. Moreover, by using an alkaline stop-fixing bath, any damage to the layer due to carbon dioxide being liberated, which damage can occur in acid stop-bath or stop-fixing baths, is avoided.

Example 1 A multi-layer color photographic material, containing 3-(p-stearylamino lbenzoylacetamino)-isophth-alic acid as a yellow color coupler, 1-(4'-phenoxy-3'sulphophenyl)- 3-heptadecyl-5-pyrazolone as a magenta color coupler and 1-hydroxy-4sulpho-2-naphtho ic acid octadecylamide as a cyan color coupler is developer in a developer having the following composition:

G. Sodium hexametaphosphate 2 Hydroxylamine sulphate 4 Anhydrous sodium sulphite 4 Potassium bromide 1 Anhydrous potassium carbonate N-butyl-w-sulphobutyl-p araphenylene diamine 5 Made up with water to 1000 cc The material is then treated in the following stop-fixing bath:

G. Sodium hexametaphosphate 2 Potassium d-ihydrogen phosphate 30 Anhydrous sodium sulphite 4 Anhydrous sodium thiosulphate 100 Thiosemicarbazide 3 Hydrazine sulphate 2 adjusted with potassium carbonate to pH=8.0 and made up with water to 1000 cc.; then immediately in the following bleach-fixing bath:

G. Tr-isodium ethylendiamine tetraacetic acid 30 Disodium hydrogen phosphate 15 Iron salt of ethylene diamine tetraacetic acid 30 Anhydrous sodium sulphite 2 Thiosemicarbazide 3 Anhydrous sodium thiosulphate Hydrazine sulphate 2 adjusted with potassium carbonate to pH=8.0 and made up with water to 1000 cc.

The material is then rinsed, and after treatment with a formalin-containing stabilising bath of pH=7.0 it is dried.

A color image is obtained without the slightest indication of a color fogging.

Example 2 The development takes place as indicated in Example 1 and the further processing is effected in a stop-fixing bath with the following composition:

G. Sodium hexametap'hosphate 2 Potassium dihydrogen phosphate 30 Anhydrous sodium sulphite 4 Anhydrous sodium th iosulphate 100 Thiosemicanbazide 3 Hydroxyl ammonium sulphate 5 adjusted with potassium carbonate to pH=8.0 and made up with Water to 1000 cc.

The immediately following bleach-fixing bath has the following composition:

adjusted with potassium carbonate to pH=8.0 and made up with water to 1000 cc.

The material is then rinsed and, after treatment with a formalin-containing stabilising bath of pH==7 .0, the material is dried.

The color image obtained is completely free from color fogging.

The same result is obtained if the hydrazine or hydroxyl ammonium sulphate in the aforementioned example is replaced by formamidine sulphinic acid.

The baths according to the invention can have a pH value between 7 and 9 and advantageously between 7.5 and 8.0.

In the process according to the invention, the bleachfixing bath is advantageously followed by a rinsing and a stabilising bath which has a pH value of approximately 7. Interposed between the developing bath and the bleach-fixing bath is a rinsing or a stop-fixing bath, which has a pH value between 7.0 and 9.0, advantageously 7.0 and 8.0, or both.

Having thus described our invention we now state that we believe our invention to be capable of numerous variations. For example suitable bleaching agents comprises complex salts of trivalent iron (German No. 866,605) or cobalt, as de'scnibed, for example, in German No. 9'5 4,475,

preferably with hydr-oxypolycarboxylic and aminopolycarboxylic acids, are eifect-ive as bleaching agents. Complex salts of trivalent iron with aminopolycarboxylic acids such as with the following acids are particularly preferred.

Ethylenediaminetetraacetic acid;

Diethylene triaminepentaacetic acid; (HOOCCH NCH CH N- (CH COOH -CH CH N- (CH COOH) 2 Nitrilo-triacetie aoid N-(CH COOH) Ethylaminediprop-ionic acid (bis-(2-carboxyethyl)ethylamine);

H C N CH CH CO0H) 2 Any water-soluble thiosulphate may be used as fixing agent such as alkali thiosulphates or ammonium thiosulphate. The bleach-fixing bath may contain as stabilizing agents any water-soluble sulfite, bisulfiite or metasulfite. Furthermore the bleach-fixing bath may have an additional content of water-soluble iodides according to our copending application Ser. No. 95,735, now abandoned.

Moreover it is clear to those skilled in the art that the photographic material which shall the treated according to the invention may be developed by means of any developer composition known per se. The pH value of the bleach-fixing bath can be adjusted by the addition of phosphates, carbonates or borates of alkali or alkalineearth metals. The reducing agent according to the invention should be added in an amount of between 0.2-5 g. per litre, preferably in an amount of 0.5-3 g. per litre. The anion of the hydrazine respectively hydroxylamine salts to be used are not critical. Preferred are salts of the said compounds with acids such as sulphuric acid or hydrochloric acid.

We claim:

1. In a process for the production of a photographic image which comprises (a) imagewise exposure of a photographic multilayer color material comprising at least one light-sensitive silver halide emulsion layer which contains a color coupler capable of reacting with an oxidation product of a color-forming developer to form a dye.

(b) developing the said material to form a silver and a color image, and (c) simultaneously bleaching and fixing the said developed material to remove the silver image from the light-struck areas and the silver halide from the areas not struck by light by a bleach-fixing bath containing (1) a bleaching agent selected from the group consisting of ferric and cob altic complex salts of a member selected from the group consisting of hydroxypolycarboxylic and aminopolycarboxylic acids, (2) a fixing agent consisting of a water-soluble salt of thiosulfuric acid, said fixing bath having a pH value of between 7 and 9,

the improvement according to which the simultaneously bleaching and fixing is accomplished in efiective contact with a reducing agent selected from the class consisting of a hydrazine salt, a water-soluble ihydroxylamine salt and formamidine-sulphinic acid.

2. A process as defined in claim 1 in which the bleachfixing bath contains the said reducing agent in an amount of 0.2-5 g. per liter.

3. A composition for the simultaneous bleaching and fixing of an exposed and developed photographic color material comprising at least one light-sensitive silver halide emulsion layer which contains a color coupler capable of reacting with an oxidation product of a colorforming developer-to form a dye, which contains (1) a bleaching agent of the group consisting of ferric and co'baltic complex salts of a member selected from the group consisting of hydroxynolvcar-boxylic and aminopolycarboxylic acids,

(2) a fixing agent consisting of a water-soluble salt of thiosulfuric acid, and

(3) a reducing agent selected from the class consisting of a hydrazine salt, a water-soluble hydroxylamine salt and a formamidine-sulphinic acid in an amount of between 0.2 and 5 g. per liter of the composition.

4. A composition as'defined in claim 3 containing the ferric complex salt of ethylenediaminetetraacetic acid as 6 bleaching agent (I) and sodium thiosulfate as the fixing 768,401 2/1957 Great Britain. agent (II). 774,194 5/ 1957 Great Britain.

777,635 6/1957 Great Britain. References Cited by the Examiner 6 G. Primary Examiner.

14 3 2 10 195 G A. D. RICCI, Assistant Examiner. 

1. IN A PROCESS FOR THE PRODUCTION OF A PHOTOGRAPHIC IMAGE WHICH COMPRISES (A) IMAGEWISE EXPOSURE OF A PHOTOGRAPHIC MULTILAYER COLOR MATERIAL COMPRISING AT LEAST ONE LIGHT-SENSITIVE SILVER HALIDE EMULSION LAYER WHICH CONTAINS A COLOR COUPLER CAPABLE OF REACTING WITH AN OXIDATION PRODUCT OF A COLOR-FORMING DEVELOPER TO FROM A DYE, (B) DEVELOPING THE SAID MATERIAL TO FORM A SILVER AND A COLOR IMAGE, AND (C) SIMULTANEOUSLY BLEACHING AND FIXING THE SAID DEVELOPED MATERIAL TO REMOVE THE SILVER IMAGE FROM THE LIGHT-STRUCT AREAS AND THE SILVER HALIDE FROM THE AREAS NOT STRUCK BY LIGHT BY A BLEACH-FIXING BATH CONTRAINING (1) A BLEACHING AGENT SELECTED FROM THE GROUP CONSISTING OF FERRIC AND COBALTIC COMPLEX SALTS OF A MEMBER SELECTED FROM THE GROUP CONSISTING OF HYDROXYPOLYCARBOXYLIC AND AMINOPOLYCARBOXYLIC ACIDS, (2) A FIXING AGENT CONSISTING OF A WATER-SOLUBLE SALT OF THIOSULFURIC ACID, SAID FIXING BATH HAVING A PH VALUE OF BETWEEN 7 TO 9, THE IMPROVEMENT ACCORDING TO WHICH THE SIMULTANEOUSLY BLEACHING THE FIXING IS ACCOMPLISHED IN EFFECTIVE CONTACT WITH A REDUCING AGENT SELECTED FROM THE CLASS CONSISTING OF A HYDRAZINE SALT, A WATER-SOLUBLE HYDROXYLAMINE SALT AND FORMAMIDINE-SULPHINIC ACID. 